1. Technical Field
The present invention relates to a hot air blower for solder treatment which blows out hot air to a solder treatment portion at solder treatment such as soldering or removal of soldered parts and particularly to uniformity of temperature distribution of the blown-out hot air.
2. Background Art
At solder treatment such as soldering and removal of soldered parts, a hot air blower for solder treatment (hereinafter also referred to as hot air blower) which blows out hot air to a solder treatment portion has been known. This hot air blower can restrict temperature rise of an electronic part at soldering of an electronic part such as an IC by preheating an electrode portion (solder treatment portion) by the hot air so as to reduce time for soldering. Also, soldering can be carried out by melting the solder by the hot air. Moreover, when an electronic part soldered to a board is to be removed, for example, by blowing the hot air to the soldered portion (solder treatment portion) so as to melt it, the removal can be accomplished without damaging the board or electronic part.
The hot air blower is used by attaching a nozzle to a hot-air blow-out port as appropriate in many cases. The nozzle is a member for guiding the hot air so that the hot air blows to a necessary portion in a concentrated manner. Normally, parts to be soldered are different in size, shape, position of the electrode and the like, and by selectively attaching a nozzle fitted to a target part, favorable solder treatment can be accomplished efficiently.
In this type of hot air blower, it is desirable that temperature distribution of blown-out hot air is even. If the temperature distribution is largely uneven (temperature irregularity), the solder treatment portion might become partially too hot, which could adversely affect the treatment target part, or the temperature might become too low and solder treatment work can be hindered.
Then, a nozzle for making a uniform temperature distribution of the blown-out hot air as shown in Patent Document 1, for example, is proposed. In this nozzle, a hot-air reservoir chamber is provided in the middle of a passage of hot air and a rotating fan for agitation is provided in the reservoir chamber. On the upstream side of the rotating fan, a control plate having a through hole obliquely drilled is provided. And the rotating fan is configured to be driven by having the hot air having passed the through hole obliquely hit the rotating fan.
Patent Document 1: Japanese Utility Model Examined Publication No. 3-31496
However, the nozzle shown in Patent Document 1 has a complicated structure that a through hole is obliquely drilled in a control plate and a fan is rotated and moreover, since a part of thermal energy of the hot air is consumed for driving of the rotating fan, there is a problem that efficiency is poor. Also, since the rotating speed of the fan is fluctuated depending on an air amount of the hot air, the temperature distribution is easily fluctuated by the influence.